Polyester polyols from thermoplastic polyesters and dimer fatty acids

ABSTRACT

Polyester polyols made from thermoplastic polyesters are disclosed. The polyols can be made by heating a thermoplastic polyester such as virgin PET, recycled PET, or mixtures thereof, with a glycol to give a digested intermediate, which is then condensed with a dimer fatty acid to give the polyol. The invention includes a polyester polyol comprising recurring units of a glycol-digested thermoplastic polyester and a dimer fatty acid. The polyester polyol can also be made in a single step by reacting the thermoplastic polyester, glycol, and dimer acid under conditions effective to produce the polyol. High-recycle-content polyols having desirable properties and attributes for formulating polyurethane products, including aqueous polyurethane dispersions, can be made. The polyols provide a sustainable alternative to bio- or petrochemical-based polyols.

FIELD OF THE INVENTION

The invention relates to polyol compositions produced from thermoplasticpolyesters, including recycled or virgin polyethylene terephthalate. Thepolyols, which are useful for formulating polyurethanes and othercondensation polymers, incorporate a dimer fatty acid.

BACKGROUND OF THE INVENTION

Aromatic polyester polyols are commonly used intermediates for themanufacture of polyurethane products, including flexible and rigidfoams, polyisocyanurate foams, coatings, sealants, adhesives, andelastomers. The aromatic content of these polyols contributes tostrength, stiffness, and thermal stability of the urethane product.

Commonly, the aromatic polyester polyol is made by condensing aromaticdiacid, diesters, or anhydrides (e.g., terephthalic acid, dimethylterephthalate) with glycols such as ethylene glycol, propylene glycol,diethylene glycol, or the like. These starting materials usually deriveexclusively from petrochemical sources.

As companies increasingly seek to offer products with improvedsustainability, the availability of intermediates produced frombio-renewable and/or recycled materials becomes more leveraging.However, there remains a need for these products to deliver equal orbetter performance than their traditional petroleum-based alternativesat a comparable price point.

Bio-renewable content alone can be misleading as an indicator of “green”chemistry. For example, when a food source such as corn is needed toprovide the bio-renewable content, there are clear trade-offs betweenfeeding people and providing them with performance-based chemicalproducts. Additionally, the chemical or biochemical transformationsneeded to convert sugars or other bio-friendly feeds to useful chemicalintermediates such as polyols can consume more natural resources andenergy and can release more greenhouse gases and pollutants into theenvironment than their petro-based alternatives in the effort to achieve“green” status.

Waste thermoplastic polyesters, including waste polyethyleneterephthalate (PET) streams (e.g., from plastic beverage containers),provide an abundant source of raw material for making new polymers.Usually, when PET is recycled, it is used to make new PET beveragebottles, PET fiber, or it is chemically transformed to producepolybutylene terephthalate (PBT). Other recycled raw materials are alsoavailable. For example, recycled propylene glycol is available fromaircraft or RV deicing and other operations, and recycled ethyleneglycol is available from spent vehicle coolants.

Urethane formulators demand polyols that meet required specificationsfor color, clarity, hydroxyl number, functionality, acid number,viscosity, and other properties. These specifications will vary anddepend on the type of urethane application. For instance, rigid foamsgenerally require polyols with higher hydroxyl number than the polyolsused to make flexible foams.

Polyols suitable for use in making high-quality polyurethanes haveproven difficult to manufacture from recycled materials, includingrecycled polyethylene terephthalate (rPET). Many references describedigestion of rPET with glycols (also called “glycolysis”), usually inthe presence of a catalyst such as zinc or titanium. Digestion convertsthe polymer to a mixture of glycols and low-molecular-weight PEToligomers. Although such mixtures have desirably low viscosities, theyoften have high hydroxyl numbers or high levels of free glycols.Frequently, the target product is a purified bis(hydroxyalkyl)terephthalate (see, e.g., U.S. Pat. Nos. 6,630,601, 6,642,350, and7,192,988) or terephthalic acid (see, e.g., U.S. Pat, No. 5,502,247).Some of the efforts to use glycolysis product mixtures for urethanemanufacture are described in a review article by D. Paszun and T.Spychaj (Ind. Eng. Chem. Res. (1997) 1373.

Most frequently, ethylene glycol is used as the glycol reactant forglycolysis. This is sensible because it minimizes the possible reactionproducts. Usually, the glycolysis is performed under conditionseffective to generate bis(hydroxyethyl) terephthalate (“BHET”), althoughsometimes the goal is to recover pure terephthalic acid. When ethyleneglycol is used as a reactant, the glycolysis product is typically acrystalline or waxy solid at room temperature. Such materials are lessthan ideal for use as polyol intermediates because they must beprocessed at elevated temperatures. Polyols are desirably free-flowingliquids at or close to room temperature.

Dimer fatty acids (also called “dimerized fatty acids” or “dimer acids”)are chemical intermediates made by dimerizing unsaturated fatty acids(e.g., oleic acid, linoleic acid, ricinoleic acid) in the presence of acatalyst, such as a bentonite or montmorillonite clay. Commerciallyavailable dimer fatty acids are usually mixtures of products in whichthe dimer acid predominates. Some commercial dimer acids are made bydimerizing tall oil fatty acids. Dimer fatty acids are commonly used tosynthesize polyimide resins used in inks and hot-melt adhesives (see,e.g., U.S. Pat. No. 5,138,027). They are also components of alkydresins, adhesives, surfactants, and other products.

Less commonly, dimer fatty acids are used as urethane components,particularly when the urethane includes a recycled PET-based polyol. Oneexception is JP 2004-307583, which describes a method for producing apolyester polyol and cured polyurethane. The '583 publication describesa two-step method in which recycled PET is digested with a glycol in thepresence of a transesterification catalyst. The resulting product isthen reacted with a polybasic acid having 20 or more carbons and nopolymerizable double bond. Dimer acids are taught as suitable polybasicacids for the second step. The reaction product is subsequently reactedwith MDI to make a simple urethane coating. In the working examples, arelatively large proportion of dimer fatty acid is used (one or moreequivalents of dimer acid per equivalent of recycled PET), and it isunclear whether satisfactory results could be obtained with less dimerfatty acid. The large proportion of dimer fatty acid also severelylimits the amount of recycle content (rPET plus any recycled glycol) inthe polyol.

Improved polyols are needed. In particular, the urethane industry needssustainable polyols based in substantial part on recycled polymers suchas the practically unlimited supply of recycled polyethyleneterephthalate. Polyols with high recycle content that satisfy thedemanding color, clarity, viscosity, functionality, and hydroxyl contentrequirements of polyurethane formulators would be valuable.

SUMMARY OF THE INVENTION

The invention relates to polyester polyols and processes for makingthem. In one aspect, the polyol is made by a process which comprises twosteps. First, a thermoplastic polyester such as PET, recycled PET, ortheir mixtures, is heated with a glycol to give a digested intermediate.The intermediate is then condensed with a dimer fatty acid to give thepolyol. In another aspect, the invention relates to a polyester polyolcomprising recurring units of a glycol-digested thermoplastic polyesterand a dimer fatty acid. In both aspects, the molar ratio of dimer fattyacid to thermoplastic polyester is less than 0.8, the molar ratio ofglycol to thermoplastic polyester is at least 2.0, and the polyol has ahydroxyl number within the range of 25 to 800 mg KOH/g. The polyesterpolyol can also be made in a single step by reacting the thermoplasticpolyester, glycol, and dimer acid under conditions effective to producethe polyol. Aqueous polyurethane dispersions made from the polyols arealso included.

We surprisingly found that high-recycle-content polyols having desirablehydroxyl numbers, viscosities, appearance, and other attributes forformulating polyurethane products can be made by reacting, at certainequivalent ratios, a glycol-digested thermoplastic polyester, preferablya digested PET, and a dimer fatty acid. The polyols, which are valuablefor formulating a variety of polyurethanes and relatedproducts—including polyurethane dispersions, flexible and rigid foams,coatings, adhesives, sealants, and elastomers—provide a sustainablealternative to bio- or petrochemical-based polyols.

DETAILED DESCRIPTION OF THE INVENTION

In one aspect, polyester polyols made by a two-step process aredisclosed. A thermoplastic polyester is first heated with a glycol togive a digested intermediate. The digested intermediate is subsequentlycondensed with a dimer fatty acid to give the polyol.

Thermoplastic polyesters suitable for use are well known in the art.They are condensation polymers produced from the reaction of glycols andaromatic dicarboxylic acids or acid derivatives. Examples includepolyethylene terephthalate (PET); polybutylene terephthalate (PBT);polytrimethylene terephthalate (PIT); glycol-modified polyethyleneterephthalate (PETG); copolymers of terephthalic acid and1,4-cyclohexanedimethanol (PCT); PCTA (an isophthalic acid-modifiedPCT); polyhydroxy alkanoates, e.g., polyhydroxybutyrate; copolymers ofdiols with 2,5-furandicarboxylic acid or dialkyl2,5-furandicarboxylates, e.g., polyethylene furanoate; copolymers of2,2,4,4-tetramethyl-1,3-cyclobutanediol with isophthalic acid,terephthalic acid or orthophthalic derivatives; dihydroferulic acidpolymers; and the like, and mixtures thereof. Further examples ofpolyester thermoplastics are described in Modern Polyesters: Chemistryand Technology of Polyesters and Copolyesters, J. Scheirs and T. Long,eds., Wiley Series in Polymer Science, 2003, John Wiley & Sons, Ltd.Hoboken, N.J. Other examples of thermoplastic polyesters may be found inChapters 18-20 of Handbook of Thermoplastics, O. Olabisi, ed., 1997,Marcel Dekker, Inc. New York. Suitable thermoplastic polyesters includevirgin polyesters, recycled polyesters, or mixtures thereof.Polyethylene terephthalate is particularly preferred, especiallyrecycled polyethylene terephthalate (rPET), virgin PET, and mixturesthereof. For more examples of suitable thermoplastic polyesters, seeU.S. Pat. Appl. Publ. No. 2009/0131625, the teachings of which areincorporated herein by reference.

Recycled polyethylene terephthalate suitable for use in making theinventive polyester polyols can come from a variety of sources. The mostcommon source is the post-consumer waste stream of PET from plasticbottles or other containers. The rPET can be colorless or contain dyes(e.g., green, blue, or other colors) or be mixtures of these. A minorproportion of organic or inorganic foreign matter (e.g., paper, otherplastics, glass, metal, etc.) can be present. A desirable source of rPETis “flake” rPET, from which many of the common impurities present inscrap PET bottles have been removed in advance. Another desirable sourceof rPET is pelletized rPET, which is made by melting and extruding rPETthrough metal filtration mesh to further remove particulate impurities.Because PET plastic bottles are currently manufactured in much greaterquantity than any recycling efforts can match, scrap PET will continueto be available in abundance.

Glycols suitable for use are well known. By “glycol,” we mean a linearor branched, aliphatic or cycloaliphatic compound or mixture ofcompounds having two or more hydroxyl groups. Other functionalities,particularly ether or ester groups, may be present in the glycol. Inpreferred glycols, two of the hydroxyl groups are separated by from 2 to10 carbons, preferably 2 to 5 carbons. Suitable glycols include, forexample, ethylene glycol, propylene glycol, 1,3-propanediol,1,2-butylene glycol, 1,3-butylene glycol, 1,4-butanediol,2-methyl-1,3-propanediol, pentaerythritol, sorbitol, neopentyl glycol,glycerol, trimethylolpropane, 2,2,4,4-tetramethyl-1,3-cyclobutanediol,3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol,1,3-cyclohexanedimethanol, bisphenol A ethoxylates, diethylene glycol,dipropylene glycol, triethylene glycol, 1,6-hexanediol, tripropyleneglycol, tetraethylene glycol, polyethylene glycols having a numberaverage molecular weight up to about 400 g/mol, block or randomcopolymers of ethylene oxide and propylene oxide, and the like, andmixtures thereof. Propylene glycol is particularly preferred. In apreferred aspect, the glycol is a recycled glycol, especially recycledpropylene glycol. Propylene glycol recovered from used deicing fluids isone example.

The thermoplastic polyester and glycol are heated, optionally in thepresence of a catalyst, to give a digested intermediate. The digestedintermediate will commonly be a mixture of glycol reactant, glycol(s)generated from the thermoplastic polyester, terephthalate oligomers, andother glycolysis products. For example, when PET or rPET is thethermoplastic polyester, the digested intermediate will include amixture of glycol reactant, ethylene glycol (generated from the PET orrPET), bis(2-hydroxyalkyl) terephthalate (“BHAT”), higher PET oligomers,and other glycolysis products. Similar digested mixtures in variousforms have been made and characterized previously (see, e.g., a Paszunet al., Ind. Eng. Chem. Res. 36 (1997) 1373 and N. Ikladious, J. Elast.Plast. 32 (2000) 140). Heating is advantageously performed attemperatures within the range of 80° C. to 260° C., preferably 100° C.to 240° C., more preferably 130° C. to 210° C., and most preferably 160°C. to 185° C.

In one aspect, when the thermoplastic polyester is polyethyleneterephthalate, the digested intermediate comprises glycols and aterephthalate component. The terephthalate component preferablycomprises, by gel permeation chromatography using ultraviolet detection,45 to 70 wt. % of bis(hydroxyalkyl)terephthalates. In a preferredaspect, the terephthalate component further comprises 20 to 40 wt. % ofterephthalate dimers. In another preferred aspect, the terephthalatecomponent of the digested intermediate comprises 45 to 65 wt. % ofbis(hydroxyalkyl)terephthalates, 20 to 35 wt. % of terephthalate dimers,and 5 to 15 wt. % of terephthalate trimers. In another preferred aspect,the terephthalate component comprises 50 to 60 wt. % ofbis(hydroxyalkyl)-terephthalates, 25 to 30 wt. % of terephthalatedimers, and 8 to 12 wt. % of terephthalate trimers.

Catalysts suitable for making the digested intermediate are well known(see, e.g., K. Troev et al., J. Appl. Polym. Sci. 90 (2003) 1148). Inparticular, suitable catalysts comprise titanium, zinc, antimony,germanium, zirconium, manganese, or other metals. Specific examplesinclude titanium alkoxides (e.g., tetrabutyl titanate), titanium(IV)phosphate, zirconium alkoxides, zinc acetate, lead acetate, cobaltacetate, manganese(II) acetate, antimony trioxide, germanium oxide, orthe like, and mixtures thereof. Catalysts that do not significantlypromote isocyanate reaction chemistries are preferred. The amount ofcatalyst used is typically in the range of 0.005 to 5 wt. %, preferably0.01 to 1 wt. %, more preferably 0.02 to 0.7 wt. %, based on the totalamount of polyol being prepared.

Usually, the digestion reaction is performed by heating thethermoplastic polyester, glycol(s), and any catalyst at least until themixture liquefies and particles of the thermoplastic polyester are nolonger apparent. Reaction times range from about 30 minutes to about 16hours, more typically 1 to 10 hours, even more typically 3 to 8 hours,and will depend on the reaction temperature, source of the thermoplasticpolyester, the particular glycol reactant used, mixing rate, desireddegree of depolymerization, and other factors that are within theskilled person's discretion.

The molar ratio of glycol to thermoplastic polyester is at least 2.0,preferably 2.0 to 6.0, more preferably 2.5 to 4.5. When theglycol/thermoplastic polyester molar ratio is below 2.0, the productsare often solids or too viscous to be practical for use as polyols. Onthe other hand, when the glycol/thermoplastic polyester molar ratio isgreater than about 6, the hydroxyl numbers tend to exceed the practicalupper limit of about 800 mg KOH/g.

In a second reaction step, the digested intermediate described above iscondensed with a dimer fatty acid to give the inventive polyesterpolyol. As used herein, “dimer fatty acid” is synonymous with “dimerizedfatty acid” or “dimer acid.” Dimer fatty acids are chemicalintermediates made by dimerizing unsaturated fatty acids (e.g., oleicacid, linoleic acid, linolenic acid, ricinoleic acid) in the presence ofa catalyst, such as a bentonite or montmorillonite clay. Commerciallyavailable dimer fatty acids are usually mixtures of products in whichthe dimerized product predominates. Some commercial dimer acids are madeby dimerizing tall oil fatty acids. Dimer fatty acids frequently have 36carbons and two carboxylic acid groups. They may be saturated orunsaturated. They may also be hydrogenated to remove unsaturation. In apreferred aspect, the dimer fatty acid comprises dimerized oleic acid,trimerized oleic acid, dimerized linoleic acid, trimerized linolelicacid, dimerized linolenic acid, trimerized linolenic acid, or mixturesthereof. Suitable dimer fatty acids include Pripol™ dimer fatty acids(products of Croda) such as Pripol™ 1006, 1009, 1010, 1012, 1013, 1017,1022, 1025, 1027, 1029, 1036, and 1098; Unidyme™ dimer acids (productsof Arizona Chemical) such as Unidyme 10, 14, 18, 22, 35, M15, and M35;dimer acids available from Emery Oleochemicals, and FloraDyme™ dimeracids from Fiorachem Corporation.

Methods for synthesizing dimer fatty acids suitable for use are alsoknown. Fatty acids having at least one carbon-carbon double bond aredimerized in the presence of a catalyst such as a montmorillonite,kaolinite, hectorite, or attapulgite clay (see, e.g., U.S. Pat. Nos.2,793,220, 4,371,469, 5,138,027, and 6,281,373, the teachings of whichare incorporated herein by reference; see also WO 2000/075252 and CA104511).

The reaction between the digested intermediate and the dimer fatty acidis performed under conditions effective to promote condensation betweenone or more acid groups of the dimer fatty acid and hydroxyl groupspresent in the digested intermediate. The condensation is preferablyperformed by heating at temperatures within the range of 80° C. to 260°C., preferably 100° C. to 240° C., more preferably 130° C. to 230° C.,and most preferably 160° C. to 210° C. Water generated in this reactionis advantageously removed from the reaction mixture as it forms. On alab scale, it is convenient to use a Dean-Stark trap or similarapparatus to remove the water of reaction, but other means will be morepractical on a larger scale. Continuous processes for water removal,such as vacuum stripping, wiped-film evaporation, and the like, may bedesirable. The condensation reaction is normally continued until apre-determined amount of water has been collected or a target acidnumber and/or hydroxyl number is reached for the product.

The molar ratio of dimer fatty acid to thermoplastic polyester is lessthan 0.8, preferably less than 0.7, more preferably less than 0.6. Themolar ratio of dimer fatty acid to thermoplastic polyester is preferablywithin the range of 0.1 to 0.6, more preferably 0.2 to 0.5. When themolar ratio is less than 0.1, there is too little benefit from includingthe dimer fatty acid in terms of generating useful polyols (forinstance, the hydroxyl numbers reach or exceed their useful upperlimit). When the molar ratio is greater than 0.8, formulation cost ishigher than desirable, recycle content drops, and there is little or noadditional performance benefit.

As long as some dimer fatty acid is used to make the polyol, one or moreother dicarboxylic acids can also be included. Instead of including adicarboxylic acid, a diester, or an anhydride can be used. Suitabledicarboxylic acids include, for example, glutaric acid, adipic acid,succinic acid, cyclohexane dicarboxylic acids, maleic acid, fumaricacid, itaconic acid, phthalic acid, 1,5-furandicarboxylic acid,isophthalic acid, and anhydrides thereof (e.g., maleic anhydride,phthalic anhydride, itaconic anhydride, and the like). Mixtures ofdicarboxylic acids can be used, including, e.g., the commerciallyavailable mixture of dibasic acids known as “DBA.” A typical DBAcomposition might contain 51-61 wt. % glutaric acid, 18-28 wt. %succinic acid, and 15-26 wt. % adipic acid.

Preferably, when another dicarboxylic acid is included, the dimer fattyacid is present in a greater molar proportion compared with theadditional dicarboxylic acid. When the molar amount of dicarboxylic acidexceeds that of the dimer fatty acid, the polyol product has a greatertendency to solidify, has higher viscosity, and is prone to settling.

In another aspect, the polyester polyol is made in a single step byreacting the thermoplastic polyester, glycol, and dimer fatty acid underconditions effective to produce the polyol. As with polyols made usingthe two-step process, the molar ratio of dimer fatty acid tothermoplastic polyester is less than 0.8, the molar ratio of glycol tothermoplastic polyester is at least 2.0, and the resulting polyol has ahydroxyl number within the range of 25 to 800 mg KOH/g. When thesingle-step process is used, it is preferred to utilize a condensationsystem that returns glycols to the reaction vessel while allowingremoval of water, as removal of too much glycol can result in cloudy oropaque polyols. Example 11 below illustrates the single-step process.

The inventive polyester polyols have hydroxyl numbers within the rangeof 25 to 800 mg KOH/g, preferably 40 to 500 mg KOH/g, more preferably200 to 400 mg KOH/g. Hydroxyl number can be measured by any acceptedmethod for such a determination, including, e.g., ASTM E-222 (“StandardTest Methods for Hydroxyl Groups Using Acetic Anhydride Acetylation”).

The inventive polyols preferably have average hydroxyl functionalities(i.e., the average number of —OH groups per molecule) within the rangeof 1.5 to 3.5, more preferably 1.8 to 2.5, and most preferably 2.0 to2.4.

The inventive polyols are flowable liquids under ambient conditions.Preferably, the polyols have viscosities measured at 25° C. less than30,000 cP, more preferably less than 20,000 cP, most preferably lessthan 10,000 cP. A preferred range for the polyol viscosity is 300 to5,000 cP, more preferably 500 to 3,900 cP. Viscosity can be determinedby any industry-accepted method. It is convenient to use, for instance,a Brookfield viscometer (such as a Brookfield DV-III Ultra rheometer)fitted with an appropriate spindle, and to measure a sample at severaldifferent torque settings to ensure an adequate confidence level in themeasurements.

The polyols preferably have low acid numbers. Urethane manufacturerswill often require that a polyol have an acid number below a particularspecification. Low acid numbers can be ensured by driving thecondensation step (with dimer fatty acid) to the desired level ofcompletion or by adding a neutralizing agent (e.g., sodium hydroxide) atthe conclusion of the condensation step. Preferably, the polyols have anacid number less than 30 mg KOH/g, more preferably less than 10 mgKOH/g, and most preferably less than 5 mg KOH/g. As suggested above, itis acceptable practice to adjust acid numbers if necessary for aparticular application with an acid scavenger such as, for example, anepoxide derivative, and this treatment can be performed by themanufacturer, distributor, or end user.

An advantage of the polyester polyols is their reduced reliance on bio-or petrochemical sources for raw material. Preferably, the polyolsinclude greater than 10 wt. %, more preferably greater than 25 wt. %,most preferably greater than 50 wt. % of recycle content. A preferredrange for the recycle content is 25 to 98,5 wt. %. By “recycle content,”we mean the combined amounts of thermoplastic polyester and any recycledglycol or dicarboxylic acid. Some glycols, such as propylene glycol orethylene glycol, are available as recovered or recycled materials. Forinstance, propylene glycol is used in deicing fluids, and after use, itcan be recovered, purified, and reused. Usually, the dimer fatty acid isprepared from renewable resources. Recycle content can be calculated,for instance, by combining the masses of thermoplastic polyester and anyrecycled PG or recycled dicarboxylic acids, dividing this sum by thetotal mass of reactants (glycols, thermoplastic polyester, dimer acid,and any dicarboxylic acids), and then multiplying the result by 100.

Although performance in the ultimate end use is paramount, urethanemanufacturers like to purchase polyols that look good. When otherconsiderations are equal, a transparent (or nearly transparent) polyolmay be more attractive than an opaque one. (“Dispersion polyols” or“polymer polyols,” which are common components of the load-bearing,high-resiliency urethane foams used in automotive seating or furnitureapplications, are a notable exception; they are supposed to appearopaque.) Unlike known polyols that are made by reacting thermoplasticpolyester digestion products with dicarboxylic acids such as succinicacid or phthalic anhydride, which are often opaque, the inventivepolyols are frequently transparent or nearly so. This is particularlytrue when the molar ratio of glycol to thermoplastic polyester is keptwithin the range of 2.5 to 4.

Yet another desirable polyol attribute is the absence of settling,particularly upon prolonged storage. When settling is substantial, thepolyol might have to be filtered or otherwise treated to remove thesolids content; this is preferably avoided. Preferred inventive polyolsexhibit no settling or only a slight degree of settling, and morepreferred polyols exhibit no evidence of settling.

In another aspect, the invention includes a polyester polyol comprisingrecurring units of a glycol-digested thermoplastic polyester and a dimerfatty acid, wherein the molar ratio of dimer fatty acid to thermoplasticpolyester is less than 0.8, the molar ratio of glycol to thermoplasticpolyester is at least 2.0, and the polyol has a hydroxyl number withinthe range of 25 to 800 mg KOH/g. The glycol-digested thermoplasticpolyester and dimer fatty acid have already been described above.“Recurring units” means that the polyester polyol includes one or moreunits derived from each of the dimer fatty acid and the glycol-digestedthermoplastic polyester.

In a specific aspect, the invention relates to a process whichcomprises: (a) heating virgin PET, recycled PET, or a mixture thereofwith propylene glycol in the presence of a zinc or titanium catalyst togive a digested intermediate; and (b) condensing the intermediate with adimer fatty acid to give the polyol; wherein the molar ratio of dimerfatty acid to PET is less than 0.6, the molar ratio of glycol to PET iswithin the range of 2.5 to 4.5, and the polyol has a hydroxyl numberwithin the range of 40 to 500 mg KOH/g, a viscosity at 25° C. less than5,000 cP, and a recycle content as defined herein greater than 25 wt. %.

The inventive polyester polyols can be used to formulate a wide varietyof polyurethane products. By adjusting the proportion of dimer fattyacid used, a desired degree of polyol hydrophobicity can be “dialed in.”The ability to control hydrophobicity is particularly valuable in thecoatings industry. The polyols can be used for cellular, microcellular,and non-cellular applications including flexible foams, rigid foams(including polyisocyanurate foams), urethane dispersions, coatings,adhesives, sealants, and elastomers. The resulting polyurethanes arepotentially useful for automotive and transportation applications,building and construction products, marine products, packaging foam,flexible slabstock foam, carpet backing, appliance insulation, castelastomers and moldings, footwear, biomedical devices, and otherapplications.

Further, the inventive polyester polyols may be derivatized to formmono-, di- and polyacrylates via esterification or transesterificationwith acrylic acid or methacrylic acid-derived raw materials. Examples of(meth)acrylation raw materials suitable for forming (meth)acrylatederivatives of the inventive polyester polyols include acryloylchloride, methacryloyl chloride, methacrylic acid, acrylic acid, methylacrylate, methyl methacrylate, and the like, or mixtures thereof. Such(meth)acrylate-derivatized inventive polyester polyols are useful forradiation or UV cure coating formulations or applications. Prepolymersof the inventive polyester polyols may be derivatized to form urethane(meth)acrylates via reaction with hydroxyethyl (meth)acrylate. Theresulting urethane acrylates may also be used in radiation or UV-curecoating formulations or applications.

In a particular aspect, the invention relates to aqueous polyurethanedispersions made from the inventive polyester polyols. We found that thedimer fatty acid-modified polyols are readily formulated into aqueouspolyurethane dispersions having a desirable balance of properties,including high solids, low viscosities, and a low tendency to settle.Numerous ways to formulate aqueous polyurethane dispersions are knownand suitable for use. Preferably, the polyurethane dispersion is made byemulsifying an isocyanate-terminated prepolymer in water with the aid ofan emulsifying agent. Water, a water-soluble polyamine chain extender,or a combination thereof may be used to react with the emulsifiedprepolymer. The prepolymer is preferably made by reacting an inventivepolyester polyol, a hydroxy-functional emulsifier, one or more auxiliarypolyols, and one or more polyisocyanates. The aqueous polyurethanedispersions are preferably used to formulate water-borne coatings,adhesives, sealants, elastomers, and similar urethane products, and theyare particularly valuable for reducing reliance on solvents. Forinstance, the dispersions can be used to formulate low- or zero-VOCcompositions.

Polyisocyanates suitable for use in making the prepolymers are wellknown; they include aromatic, aliphatic, and cycloaliphaticpolyisocyanates. Examples include toluene diisocyanates (TDs), MDIs,polymeric MDIs, naphthalene diisocyanates (NDIs), hydrogenated MDIs,trimethyl- or tetramethylhexamethylene diisocyanates (TMDIs),hexamethylene diisocyanate (HDI), isophorone diisocyanates (IPDIs),cyclohexane diisocyanates (CHDIs), xylylene diisocyanates (XDI),hydrogenated XDIs, and the like. Aliphatic diisocyanates, such ashexamethylene diisocyanate and isophorone diisocyanates are particularlypreferred.

Auxiliary polyols suitable for use are also well known. They includepolyether polyols, aliphatic polyester polyols, aromatic polyesterpolyols, polycarbonate polyols, glycols, and the like. Preferredauxiliary polyols have average hydroxyl functionalities within the rangeof 2 to 6, preferably 2 to 3, and number average molecular weightswithin the range of 500 to 10,000, preferably 1,000 to 8,000. Preferredpolyester polyols are condensation products of dicarboxylic acids anddiols or triols (e.g., ethylene glycol, propylene glycol,2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 1,4-butanediol,neopentyl glycol, glycerin, trimethylolpropane,1,4-cyclohexanedimethanol, bisphenol A ethoxylates), especially diols.The dicarboxylic acids can be aliphatic (e.g., glutaric, adipic,succinic) or aromatic (e.g., phthalic), preferably aliphatic.

A hydroxy-functional emulsifier is also used to make the polyurethanedispersions. The role of this component is to impartwater-dispersibility to the prepolymer, usually upon its combinationwith water and a neutralizing agent, such as an acid or base reactant.Thus, in one aspect, the hydroxy-functional emulsifier is anacid-functional diol such as dimethylolpropionic acid (DMPA) ordimethylolbutanoic acid (DMBA). The acid functionality in the resultingprepolymer allows for neutralization with an amine or other basicreactant to generate a water-dispersible urethane. Thehydroxy-functional emulsifier can also be an amine, such asN-methyldiethanolamine. Neutralization of the resulting prepolymer withan acidic reagent renders it water dispersible. In other aspects, thehydroxy-functional emulsifier is nonionic, e.g., a polyethylene glycolmonomethyl ether. In another aspect, the hydroxy-functional emulsifiermay be a monol- or diol-functionalized poly(ethylene oxide), such as forexample Ymer™ N120 dispersing monomer (product of Perstorp), or themethyl ether of polyethylene glycol. Additionally, non-reactive,so-called “external emulsifiers,” such as the triethanolamine salt ofdodecylbenzene sulfonic acid, may be included in the aqueous phase toassist in the emulsification and stabilization of the prepolymer andresulting polyurethane dispersion.

In certain aspects, a chain terminator may be used to control themolecular weight of polyurethane polymer contained within the aqueouspolyurethane dispersion. Monofunctional compounds, such as thosecontaining hydroxyl, amino, and thio groups that have a single activehydrogen-containing group, are suitable chain terminators. Examplesinclude alcohols, amines, thiols, and the like, especially primary andsecondary aliphatic amines.

Chain extenders can also be included in making the polyurethanedispersion. In some aspects, the chain extender is added in an amountsufficient to react 5 to 105 mole % of free NCO groups present. Suitablechain extenders contain at least two functional groups that are capableof reacting with isocyanates, e.g., hydroxyl, thio, or amino groups inany combination. Suitable chain extenders include, for example, diols(ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol,1,4-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol,1,4-cyclohexanedimethanol, and the like), di- and polyamines(ethylenediamine, diethylenetriamine, Jeffamine® T-403, Jeffamine®D-230, Jeffamine® ED 2001, Jeffamine® ED-600, Jeffamine® ED 900,1,6-hexamethylenediamine, butylenediamine, hydrazine, piperazine,N-hydroxyethyl ethylenediamine) alkanolamines (ethanolamine,diethanolamine, N-methyl diethanolamine, and the like), dithiols, andthe like. Diol chain extenders are preferably added during thepreparation of the prepolymer, and prior to emulsification in water.

In a specific example, shown below, the dimer fatty acid-modifiedpolyester polyol, an acid-functional diol (DMPA), and auxiliary polyols(polyethylene glycol 200 and a polyester polyol made from3-methyl-1,5-pentanediol and adipic acid) are combined and reacted witha mixture of aliphatic diisocyanates (hexamethylene diisocyanate andisophorone diisocyanate) in the presence of a tin catalyst (dibutyltindilaurate) or a bismuth catalyst (such as bismuth dioctanoate) and asolvent (acetone). The resulting prepolymer is then dispersed in amixture of water, triethanolamine (neutralizing agent), and a siliconedefoamer. The resulting product is an aqueous polyurethane dispersionhaving high solids content (30%), low viscosity, and desirable settlingproperties.

For more examples of suitable approaches for preparing aqueouspolyurethane dispersions, see U.S. Pat. Nos. 5,155,163; 5,608,000;5,763,526; 6,339,125; 6,635,723, 7,045,573; and 7,342,068, the teachingsof which are incorporated herein by reference.

In another aspect, the invention relates to associative rheologymodifiers made from the dimer fatty acid-modified polyester polyols. By“associative rheology modifier,” we mean an additive used to thicken orafter the viscosity of a product. Associative thickening may involvedynamic, non-specific interactions of hydrophobic end groups of athickener molecule with itself and with other components of aformulation. Associative thickening is particularly applicable towater-based paints and coatings, where the rheology modifier, by virtueof inter- and intra-molecular network formations, is able to modifygloss, flow, shear, leveling, spatter resistance, or other properties.In addition to paints or coatings, suitable formulations might includesealants, pharmaceuticals, cosmetics, or other products that can benefitfrom rheology modification. Certain categories of associative rheologymodifiers are well known and can be formulated using the inventivepolyester polyols alone or, more often, in combination with other polyolcomponents. Such rheology modifiers include, for example,hydrophobically modified ethoxylated urethanes (“HEUR”), hydrophobicallymodified alkali-swellable emulsions (“HASE”), and hydrophobicallymodified polyethers (“HMPE”). Suitable HASE modifiers include, e.g.,hydrophobically modified polyacrylates. A typical HEUR might beassembled from a hydrophilic diol (e.g., a polyethylene glycol of6,000-8,000 g/mol), a polyisocyanate, and a hydrophobic mono or diol.The inventive polyester polyols can be utilized to supplement or replacethe hydrophobic mono or diol. For examples of HEUR, HASE, and HMPEassociative rheology modifiers and their methods of preparation, seeU.S. Pat. Nos. 8,871,817; 8,673,275; 8,697,797; 8,524,649; 8,461,213;8,334,357; 6,337,366; 5,574,127; 5,281,654; 4,155,892; and 4,079,028 theteachings of which are incorporated herein by reference.

The following examples merely illustrate the invention; the skilledperson will recognize many variations that are within the spirit of theinvention and scope of the claims.

Preparation of Dimer Fatty Acid-Modified Polyols: General Procedure

A reactor equipped with an overhead mixer, condenser, heating mantle,thermocouple, and nitrogen inlet is charged with zinc acetate dihydrate(0.55 wt. %), titanium(V) butoxide (500-1000 ppm), or no catalyst (Ex.32); recycled polyethylene terephthalate pellets; and glycol in theproportions shown in Table 1. The mixture is heated without stirring toabout 130° C. Stirring is then commenced at 60 rpm, and heatingcontinues until the reactor contents reach 180° C. The mixture is heateduntil no particles of recycled PET remain (about 4 h). When thedigestion reaction is considered complete, the mixture is cooled toabout 100° C. Dimer fatty acid (and/or dicarboxylic acid) is added (seeTable 1 for mole ratios), and the mixing rate is increased (200 rpm).The dimer fatty acid used is Pripol™ 1017, product of Croda. When theaddition is complete, a Dean-Stark trap is introduced between thereactor and condenser, and heating to 200° C. is resumed. Watergenerated in the condensation reaction is removed until roughly thetheoretical amount is removed. When the reaction is complete, the polyolproduct is allowed to cool to 100° C. and is then decanted from thereactor and filtered through cheesecloth.

The glycols used are propylene glycol, 2-methyl-1,3-propanediol,3-methyl-1,5-pentanediol, diethylene glycol, and1,4-cyclohexanedimethanol. In most examples, the dimer fatty acid(and/or dicarboxylic acid) is added following digestion of the recycledPET with the glycol, as described above. In a few examples, however, thedimer fatty acid (and/or dicarboxylic acid) is added at the outset,i.e., before digestion. Control runs in which no dimer fatty acid ordicarboxylic acid is used are also included. In some examples, thedicarboxylic acid is “DBA,” a well-known dibasic acid mixture availablefrom INVISTA and other suppliers that contains primarily glutaric acid,succinic acid, and adipic acid. A typical DBA composition might contain51-61 wt. % glutaric acid, 18-28 wt. % succinic acid, and 15-25 wt. %adipic acid. The dicarboxylic acids (or anhydrides) used are succinicacid, phthalic anhydride, adipic acid, and DBA. The digestions arecatalyzed by zinc acetate unless otherwise indicated in the tables.

“Recycle content” as used herein (wt. %) is determined by combining themasses of recycled glycol and recycled thermoplastic polyester, dividingthis sum by the total mass of reactants (e.g., glycols, rPET, dimeracid, and any dicarboxylic acids), and then multiplying the result by100.

Hydroxyl numbers and acid numbers are determined by standard methods(ASTM E-222 and ASTM D3339, respectively).

Viscosities are measured at 25° C. using a Brookfield DV-III Ultrarheometer with spindle #31 at 25%, 50%, and 75% torque.

Color, clarity, and degree of settling are evaluated visually.

Results:

As shown in Tables 1 and 2, polyols having hydroxyl numbers below 800 mgKOH/g (especially below 600 mg KOH/g), favorable viscosities (especially1000 to 4000 cP), and recycle contents greater than 10 wt. % (especiallygreater than 25%) can be made by reacting glycol-digested recycled PETwith dimer fatty acids, where the molar ratio of glycol to rPET is atleast 2.0 and the molar ratio of dimer fatty acid to rPET is less than0.8. Condensing the glycol-digested rPET with a dimer fatty acid alsomakes it possible to generate polyols that are in many casestransparent, especially when the glycol to rPET molar ratio is withinthe range of 2.5 to 4.5. If desired, some dicarboxylic acid (e.g.,succinic acid) can be included along with the dimer fatty acid, but suchproducts are typically opaque. Settling is generally avoided by usingthe preferred glycol to rPET molar ratio range of 2.5 to 4.5.

Comparative examples are provided in Tables 3 and 4. In some comparativeexamples, the glycol/rPET ratio is below 2.0, which typically results inan opaque and highly viscous or solid product. In other comparativeexamples, the glycol/rPET ratio is 2.0 or greater, but the dimer fattyacid is omitted in favor of a dicarboxylic acid or anhydride (e.g.,succinic acid, phthalic anhydride, or DBA). The products are opaque andtend to be viscous. When the glycol/rPET ratio is high (6.0 or 9.0), thehydroxyl number of the product is greater than 800 mg KOH/g. Othercomparative examples show that digestion of the rPET alone gives aproduct with desirably low viscosity but the hydroxyl numbers are toohigh to be useful.

Aqueous Polyurethane Dispersion

A DFA-modified polyol prepared as in Example 30 is used to formulate apolyurethane dispersion as follows:

A prepolymer is generated by combining the DFA-modified polyol (53.4 g),P2010 polyol (3-methyl-1,5-pentanediol adipate, 2000 mol. wt., 17.1 g,product of Kuraray), dimethylpropionic acid (9.5 g), polyethylene glycol(PEG 200, 1.33 g), acetone (140 g), and dibutyltin dilaurate (0.24 g)with hexamethylene diisocyanate (8.8 g) and isophorone diisocyanate(64.8 g). The mixture is mixed well and allowed to react at 60° C. for7.5 h to form the prepolymer mixture.

The prepolymer mixture (261 g) is combined and rapidly mixed with water(456 g), triethanolamine (14.4 g), and Byk® 028 silicone defoamer (6.21g of 10% solution in water) to generate an aqueous polyurethanedispersion. The resulting light-green dispersion has 29.7% solids,pH=8.05, and viscosity=809 cP at 21.5° C.

TABLE 1 Dimer Fatty Acid-Modified Polyol Preparation: Inventive Examplesglycol/rPET DFA/rPET DA/rPET Ex glycol(s) description (mol/mol)(mol/mol) (mol/mol) 1 2-methyl-1,3-propanediol Add dimer fatty acid(DFA) after digestion 3.0 0.50 — 2 2-methyl-1,3-propanediol Add DFAafter digestion 3.0 0.50 — 3 propylene glycol (PG) Add DFA afterdigestion 6.0 0.50 — 4 propylene glycol Add DFA after digestion 6.0 0.50— 5 propylene glycol Add DFA after digestion 9.0 0.50 — 6 propyleneglycol Add DFA after digestion 4.0 0.50 — 7 propylene glycol Add DFAafter digestion 6.0 0.50 — 8 propylene glycol Add DFA after digestion3.0 0.50 — 9 propylene glycol Add DFA after digestion 3.0 0.25 — 10propylene glycol Add DFA after digestion 3.0 0.125 — 11 propylene glycolDFA is added at the outset 3.0 0.25 — 12 propylene glycol Add DFA afterdigestion 3.0 0.25 — 13 propylene glycol Add DFA and succinic acid afterdigestion 3.0 0.25 0.25 14 propylene glycol Add DFA after digestion 2.00.25 — 15 propylene glycol Add DFA and succinic acid after digestion 3.00.375 0.125 16 propylene glycol Add DFA after digestion 2.0 0.20 — 17propylene glycol Add DFA after digestion 3.0 0.40 — 18 propylene glycolGreen pellets used. Add DFA after digestion 3.0 0.50 — 19 PG +1,4-cyclohexanedimethanol Add DFA after digestion 3.0 0.50 — 20propylene glycol Green pellets used. Add DFA after digestion 3.0 0.50 —21 propylene glycol Dilinoleic acid used as the DFA, and added afterdigestion 3.0 0.50 — 22 propylene glycol Add DFA after digestion 3.00.50 — 23 propylene glycol Add DFA after digestion 3.0 0.50 — 24propylene glycol Add DFA after digestion 3.0 0.50 — 25 propylene glycol5-L scale-up preparation 3.0 0.50 — 26 3-methyl-1,5-pentanediol Add DFAafter digestion 3.0 0.50 — 27 3-methyl-1,5-pentanediol Add DFA andphthalic anhydride after digestion 2.0 0.25 0.25 282-methyl-1,3-propanediol Add DFA after digestion 3.0 0.50 — 292-methyl-1,3-propanediol Add DFA and phthalic anhydride after digestion2.0 0.25 0.25 30 propylene glycol 5-L scale-up preparation 3.0 0.50 — 31propylene glycol Add DFA after digestion 3.0 0.65 — 32 propylene glycolAdd DFA after digestion; no catalyst used 2.8 0.46 — 33 propylene glycolAdd DFA after digestion; 500 ppm Ti(OBu)4 used 2.8 0.46 — 34 propyleneglycol Add DFA after digestion; 1000 ppm Ti(OBu)4 used 2.8 0.46 —

TABLE 2 Dimer Fatty Acid-Modified Polyol Properties: Inventive Examplesglycol/rPET DFA/rPET DA/rPET Recycle Acid # (mg OH # (mg Visc., Ex(mol/mol) (mol/mol) (mol/mol) content % KOH/g) KOH/g) Color ClaritySettling 25° C. 1 3.0 0.50 — 25.6 4.1 357 yel-amber transp. — 3517 2 3.00.50 — 25.6 4.9 318 amber transp. — 3787 3 6.0 0.50 — 69.2 3.3 614yel-amber transp. slight 751 4 6.0 0.50 — 69.2 5.4 612 grey-yel opaqueheavy 840 5 9.0 0.50 — 75.2 4.4 791 grey-green opaque heavy 385 6 4.00.50 — 63.2 4.1 439 lt. amber transp. slight 1579 7 6.0 0.50 — 69.2 1.2612 lt. amber sl. transp. yes 687 8 3.0 0.50 — 59.3 5.3 376 dk. ambersl. transp. slight 3097 9 3.0 0.25 — 74.2 6.3 522 yel-amber sl. transp.slight 1833 10 3.0 0.125 — 84.9 2.5 619 yel-amber sl. transp. slight1291 11 3.0 0.25 — 74.2 4.8 502 amber sl. transp. slight 1901 12 3.00.25 — 74.2 4.6 510 amber sl. transp. slight 1878 13 3.0 0.25 0.25 72.32.4 466 green-amber opaque slight 2121 14 2.0 0.25 — 70.2 4.2 354 yellowopaque yes 7284 15 3.0 0.375 0.125 64.4 18.6 409 amber opaque slight2340 16 2.0 0.20 — 74.5 3.5 363 yel-amber opaque heavy 7877 17 3.0 0.40— 64.5 1.9 379 amber opaque slight 3994 18 3.0 0.50 — 59.3 3.8 382 greentransp. none 3408 19 3.0 0.50 — 54.0 1.4 331 yellow opaque none 14,09720 3.0 0.50 — 59.3 2.6 381 green transp. none 3091 21 3.0 0.50 — 59.35.4 384 grey-green transp. none 3143 22 3.0 0.50 — 59.3 9.9 392 yellowtransp. none 2494 23 3.0 0.50 — 59.3 10.9 400 amber transp. slight 264224 3.0 0.50 — 59.3 9.2 392 yellow transp. none 2765 25 3.0 0.50 — 59.512.6 388 amber sl. transp. none 2805 26 3.0 0.50 — 23.0 2.8 300 ambertransp. none 2214 27 2.0 0.25 0.25 31.4 3.8 279 green-amber opaqueslight 5710 28 3.0 0.50 — 25.6 1.4 345 amber opaque none 4157 29 2.00.25 0.25 34.6 2.7 305 amber opaque none 11,790 30 3.0 0.50 — 59.3 18.1363 amber sl. transp. none 3047 31 3.0 0.65 — 54.9 15.1 282 amber sl.transl. none 5610 32 2.8 0.46 — 60.7 13.5 358 golden opaque none 3429 332.8 0.46 — 60.7 6.6 387 amber transp. none 3197 34 2.8 0.46 — 60.6 10.0382 amber transp. none 3061

TABLE 3 Comparative Examples glycol/rPET DFA/rPET DA/rPET Ex glycol(s)description (mol/mol) (mol/mol) (mol/mol) C35 propylene glycol Add DFAafter digestion 1.5 0.5 — C36 2-methyl-1,3-propanediol Add DFA afterdigestion 1.0 0.5 — C37 2-methyl-1,3-propanediol Add DFA after digestion 0.75 0.5 — C38 propylene glycol Adipic acid added at the outset,uncatalyzed 2.0 — 1.0 C39 propylene glycol Succinic acid added at theoutset, uncatalyzed 2.0 — 1.0 C40 propylene glycol Add succinic acidafter digestion, catalyzed 2.0 — 1.0 C41 propylene glycol Add succinicacid after digestion, catalyzed 6.0 — 0.5 C42 propylene glycol Addsuccinic acid after digestion, catalyzed 9.0 — 0.5 C432-methyl-1,3-propanediol Add DFA after digestion 1.0 0.5 — C44 propyleneglycol Add phthalic anhydride after digestion 0.9 — 0.2 C45 propyleneglycol Add dibasic acid mixture after digestion 2.0 — 1.0 C46 propyleneglycol Use Texaco procedure with DBA; use PG instead of DEG 2.0 — 1.0C47 propylene glycol Control: rPET digestion with no DFA or diacid 3.0 —— C48 propylene glycol Control: rPET digestion with no DFA or diacid 4.0— — C49 diethylene glycol Add DBA after digestion 2.0 — 1.0 C503-methyl-1,5-pentanediol Add phthalic anhydride after digestion 2.0 —0.5 C51 2-methyl-1,3-propanediol Add phthalic anhydride after digestion2.0 — 0.5 C52 propylene glycol Add succinic acid after digestion 3.0 —0.5 C53 propylene glycol Add adipic acid after digestion 3.0 — 0.5

TABLE 4 Comparative Examples glycol/rPET DFA/rPET DA/rPET Recycle Acid #(mg OH # (mg Visc., Ex (mol/mol) (mol/mol) (mol/mol) content % KOH/g)KOH/g) Color Clarity Settling 25° C. C35 1.5 0.5 — 51.5 2.6 256 yellowopaque — 10,969 C36 1.0 0.5 — 33.6 7.0 55 grey green opaque solid barelyflows C37 0.75 0.5 — 35.0 3.4 27 grey-green opaque solid none C38 2.0 —1.0 70.2 6.6 215 white-grey opaque solid 20,156 C39 2.0 — 1.0 74.4 5.8236 white-grey opaque solid none C40 2.0 — 1.0 73.9 11.1 326 grey-greenopaque none 62,487 C41 6.0 — 0.5 91.1 1.1 882 grey-green opaque yes 253C42 9.0 — 0.5 93.3 1.2 1022 grey opaque yes 144 C43 1.0 0.5 — 22.4 28.9— grey-amber opaque none barely flows C44 0.9 — 0.2 89.2 30.7 322tan-grey opaque — none C45 2.0 — 1.0 84.8 25.5 241 grey-amber opaquenone 26,889 C46 2.0 — 1.0 85.6 12.0 191 white-grey opaque solid none C473.0 — — 99.1 2.0 730 brown opaque slight 652 C48 4.0 — — 99.3 1.8 860green-amber sl. transp. slight 345 C49 2.0 — 1.0 41.6 7.3 217 white-greyopaque none 7056 C50 2.0 — 0.5 37.9 5.1 223 grey opaque slight 13,497C51 2.0 — 0.5 42.7 10.2 349 green-amber opaque none 35,492 C52 3.0 — 0.587.0 1.3 572 tan-green opaque slight 1250 C53 3.0 — 0.5 84.6 21.3 566tan-green opaque slight 1167

Settling Experiment

The polyurethane dispersion prepared above is filtered through a 190-μmpaint filter and into a settling cone. The cone is sealed with Parafilm®“M” laboratory film and stored for 19 days in a dark cabinet. After thesettling period is concluded, the dispersion shows no apparent settling(˜0.0 mL).

A similar polyurethane dispersion prepared from a glycol-digestedrecycled polyethylene terephthalate (0.9 propylene glycol to 1 rPET) andnot modified with dimer fatty acid has 0.4 mL of settled material after19 days.

Acrylate From DFA-Modified Polyol

A flask equipped with addition funnel, condenser, heating mantle,thermocouple, and mechanical stirring is charged with a dimer fattyacid-modified polyol (75.0 g, produced as described above from recycledpolyethylene terephthalate (28.3 wt. %), propylene glycol (31.4 wt. %),titanium(IV) butoxide (0.5 wt. %), and Pripol™ 1017 dimer fatty acid(39.8 wt. %)), tetrahydrofuran (300 mL), triethylamine (50.8 g), andphenothiazine (0.19 g). The stirred mixture is heated to 50° C. Theresulting solution is cooled to 10° C., and acryloyl chloride (44.8 g)is added over 2 h. Stirring continues for an additional 1 h. Theresulting product is filtered through Celite® 545 filter aid to removeprecipitated triethylamine hydrochloride. The filtrate is stripped undervacuum and redissolved in dichloromethane (350 mL). The organic phase iswashed with 10% aq. NaOH solution, then with 10% aq. NaCl solution, thendried (MgSO₄) and concentrated (40-60° C., 70 mm Hg). Yield: 84.6 g.Analysis by ¹H NMR spectroscopy shows that conversion to the acrylateester is complete.

Acrylate Coatings

Coatings are produced using the DFA-modified polyol acrylate describedabove and a control formulation. The control formulation (50 wt. %solids in methyl ethyl ketone (MEK)) is prepared from bisphenol Aethoxylate diacrylate (66.5 wt. %), ethylene glycol phenyl etheracrylate (26.5 wt. %), Addox™ A40 adhesion promoter (5.0 wt. %, productof Doxa Chemical), and Irgacure® 1173 photoinitiator (2.0 wt. %, productof BASF). The DFA-modified polyol acrylate formulation (50 wt. % solidsin MEK) is prepared from bisphenol A ethoxylate diacrylate (37.1 wt. %),ethylene glycol phenyl ether acrylate (15.9 wt. %), DFA modified polyolacrylate (40 wt. %, prepared as described above), Addox™ A40 adhesionpromoter (5.0 wt. %), and Irgacure® 1173 photoinitiator (2.0 wt. %).Films are drawn down to provide cured coatings having an average filmthickness of 1.6-1.8 mils. The coatings are cured with four passes of aJelight handheld UV curing lamp followed by one pass on a UV bench topconveyor unit (Heraeus Noblelight) running at 5 ft./min. Results appearin Table 5.

Testing Methods for Acrylate Coatings:

Dry film thickness is determined using a PosiTector 6000 (DefelskoCorporation) dry film thickness gauge. Konig hardness is measured usingISO 1522 using a TOC pendulum hardness tester (Model SPO500). Thefollowing ASTM test methods are used: pencil hardness: ASTM D3363;flexibility: ASTM D522; adhesion: ASTM 03359; stain testing: ASTM 01308.

TABLE 5 Acrylate Coating Results DFA-modifed Control polyol acrylateFilm thickness (mil) 1.64 1.74 Konig hardness (s) 206 151 Pencilhardness 2H 2H Cross-hatch adhesion 5B 6B Mandrel bend 1″, ⅝″, ⅛″ P, P,P P, P, P MEK double rubs >200 >200 Stain testing Methyl ethyl ketone (1h) 5 5 Isopropyl alcohol (1 h) 5 5 Mustard (1 h) 5 5 Windex ® cleaner(24 h) 4 5 Vinegar (24 h) 4 5 Water (24 h) 4 5 Water soak test (3 h;hardness, value) 4H, 1F <H, 1FRigid Foam From Dimer Fatty Acid-Modified Polyester Polyol

“Part B” components are combined in a large plastic beaker (6″ diameter,5″ tall) by mixing until homogeneous a dimer fatty acid-based polyol(mol. wt. 500, hydroxyl value=224 mg KOH/g, 70.4 wt. %, prepared fromrecycled PET (28.7 wt. %), propylene glycol (31.9 wt. %), dimer fattyacid (39.3 wt. %) and titanium(IV) butoxide (0.10 wt. %) as describedpreviously) with Fyrol™ PCF flame retardant (8.0 wt. %, product ofIsrael Chemical Ltd.), Dabco® K-15 catalyst (1.60 wt. %, Air Products),Polycat® 5 catalyst (0.13 wt. %, Air Products), Tegostab® B8465 siliconesurfactant (2.6 wt. %, Evonik), water (0.32 wt. %), and n-pentane (18.3wt. %). These percentages are based on the amount of Part B component.

“Part A,” comprised of PAPI™ 27 isocyanate (polymeric MDI, 53.3 wt. %based on the combined amounts of Parts A and B, 260 NCO/OH index,product of Dow Chemical), is then quickly added. Immediately afteraddition of Part A to Part B, the container is placed on a VOS powercontrol mixer (VWR International) equipped with 3-inch diameter Cowlesblade and mixed at up to 2000 RPM for ten seconds. The mixing time iscontrolled by an electronic timer with foot pedal attachment (GraLabModel 451). Immediately after mixing stops, the well-mixed foam ispoured into a 12″×12″×12″ cardboard box and allowed to rise. After fullycuring under ambient conditions, the foam is tested for compressivestrength (ASTM D1621) and thermal conductivity (ASTM C177).

The preceding examples are meant only as illustrations; the followingclaims define the inventive subject matter.

We claim:
 1. A polyester polyol comprising recurring units of aglycol-digested polyethylene terephthalate (PET) or glycol-modifiedpolyethylene terephthalate (PETG) and an unsaturated dimer fatty acid,wherein the glycol is selected from the group consisting of propyleneglycol, diethylene glycol, and 2-methyl-1,3-propanediol, the molar ratioof dimer fatty acid to PET or PETG is within the range of 0.1 to 0.5,the molar ratio of glycol to PET or PETG is within the range of 2.5 to4.5, and the polyol has a hydroxyl number within the range of 40 to 400mg KOH/g.
 2. The polyol of claim 1 wherein the PET is selected from thegroup consisting of virgin PET, recycled PET, and mixtures thereof. 3.The polyol of claim 1 wherein the glycol comprises a recycled glycol. 4.The polyol of claim 1 having a hydroxyl number within the range of 200to 400 mg KOH/g.
 5. The polyol of claim 1 having a viscosity at 25° C.less than 10,000 cP.
 6. A transparent polyol of claim
 1. 7. The polyolof claim 1 having a recycle content as defined herein greater than 50wt. %.
 8. The polyol of claim 1 wherein the unsaturated dimer fatty acidcomprises dimerized oleic acid, trimerized oleic acid, dimerizedlinoleic acid, trimerized linoleic acid, dimerized linolenic acid,trimerized linolenic acid, or mixtures thereof.
 9. The polyol of claim 1having an acid number of less than 10 mg KOH/g.
 10. The polyol of claim1 wherein the molar ratio of dimer fatty acid to PET or PETG is withinthe range of 0.2 to 0.5.
 11. A polyester polyol comprising recurringunits of a glycol-digested polyethylene terephthalate (PET) orglycol-modified polyethylene terephthalate (PETG) and an unsaturateddimer fatty acid, wherein the glycol is selected from the groupconsisting of sorbitol, neopentyl glycol, glycerol,2,2,4,4-tetramethyl-1,3-cyclobutanediol, 3-methyl-1,5-pentanediol,1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, bisphenol Aethoxylates, 1,6-hexanediol, block or random copolymers of ethyleneoxide and propylene oxide, and mixtures thereof, the molar ratio ofdimer fatty acid to PET or PETG is within the range of 0.1 to 0.5, themolar ratio of glycol to PET or PETG is within the range of 2.5 to 4.5,and the polyol has a hydroxyl number within the range of 40 to 400 mgKOH/g.
 12. The polyol of claim 11 wherein the PET is selected from thegroup consisting of virgin PET, recycled PET, and mixtures thereof. 13.The polyol of claim 11 wherein the glycol comprises a recycled glycol.14. The polyester polyol of claim 11 having a hydroxyl number within therange of 200 to 400 mg KOH/g.
 15. The polyester polyol of claim 11wherein the molar ratio of dimer fatty acid to PET or PETG is within therange of 0.2 to 0.5.
 16. The polyol of claim 11 having a viscosity at25° C. less than 10,000 cP.
 17. A transparent polyol of claim
 11. 18.The polyol of claim 11 having a recycle content as defined hereingreater than 50 wt. %.
 19. The polyol of claim 11 wherein theunsaturated dimer fatty acid comprises dimerized oleic acid, trimerizedoleic acid, dimerized linoleic acid, trimerized linoleic acid, dimerizedlinolenic acid, trimerized linolenic acid, or mixtures thereof.
 20. Thepolyol of claim 11 having an acid number of less than 10 mg KOH/g.